Description

<% include template_name %> includes the named template which is like get_template of the ​Python API for loading templates, for consistancy we should have a comma seperated template list similer to select_template. (Untested) Patch attached.

The point is that we shouldn't be proliferating random syntax within template tags.
The current method of parsing within a tag does little to discourage this, but people should explicitly *not* have to go and look up what random syntax someone made up for a particular tag.